Follow the electrons

Science · Matter & Materials · ages 14-16

Name ______________________ Date ____________

What is reduction?
- Gain of electrons
- Loss of electrons
- Sharing of neutrons
What is oxidation?
- Gain of electrons
- Loss of electrons
- Gain of protons
Oxidation and reduction always happen together.
Circle one: True False
Which half equation shows zinc oxidising?
- Copper ions plus electrons becoming copper
- Zinc ions plus electrons becoming zinc
- Zinc becoming zinc ions plus electrons
Zinc is dropped into copper sulfate solution. Which species is oxidised?
- Copper ions
- Zinc metal
- Sulfate ions
Why is zinc above copper in the reactivity series?
- It gives up electrons more readily
- It is heavier than copper
- It is bluer in solution
In the copper silver reaction, doubling the silver half equation changes which species is oxidised.
Circle one: True False
Copper oxide plus carbon gives copper plus carbon dioxide. Using oxygen, what oxidised?
- Copper, since it lost oxygen
- Neither changed
- Carbon, since it gained oxygen

Answer key

For grown-ups. Fold this page away before handing over the rest.

Gain of electrons · RIG: reduction is gain of electrons.
Loss of electrons · OIL: oxidation is loss of electrons.
True · Every electron lost is gained somewhere, so the two pair up.
Zinc becoming zinc ions plus electrons · Oxidation releases electrons, so electrons sit on the product side.
Zinc metal · Zinc gives electrons away, and giving electrons is oxidation.
It gives up electrons more readily · The series ranks how readily a metal gives up electrons.
False · Doubling only balances electrons gained with electrons lost. Copper still gives, silver still takes.
Carbon, since it gained oxygen · By the older definition, gaining oxygen is oxidation, so carbon oxidised.